Planetary gear train of automatic transmission for vehicle

ABSTRACT

The present disclosure provides a planetary gear train of an automatic transmission including: input and output shafts, first to fifth planetary gear sets respectively having first to third, fourth to sixth, seventh to ninth, tenth to twelfth, and thirteenth to fifteenth rotational elements, a first shaft connected with the second and fifth rotational elements and the input shaft, a second shaft connected with the fourteenth rotational element and the output shaft, a third shaft connected with the ninth and thirteenth rotational elements, a fourth shaft connected with the tenth and fifteenth rotational elements, a fifth shaft connected with the first, sixth, and seventh rotational elements, a sixth shaft connected with the third rotational element, a seventh shaft connected with the eighth and eleventh rotational element, an eighth shaft connected with the fourth rotational element, and a ninth shaft connected with the twelfth rotational element.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2017-0058306 filed on May 10, 2017, which isincorporated herein by reference in its entirety.

FIELD

The present disclosure relates to an automatic transmission for avehicle.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

In the field of an automatic transmission, more multiplicity ofshift-stages is useful technology for enhancement of fuel consumptionand drivability of a vehicle.

Achieving more shift stages contributes to improve performance andefficiency of a vehicle in a trend so-called downsizing of an engine,and more linearity in step ratios of the shift-stages enhancesdrivability of the vehicle by improving uniformity of accelerationbefore and after a shifting, etc.

In order to achieve more shift-stages for an automatic transmission, thenumber of parts is typically increased, which may negatively affectinstallability, production cost, weight and/or power flow efficiency.

Therefore, in order to enhance fuel consumption of an automatictransmission having more shift-stages, it is desired that betterefficiency is derived with less number of parts.

In this aspect, an eight-speed automatic transmission has beenintroduced recently and a planetary gear train for an automatictransmission enabling more shift-stages has been investigated.

A recent eight-speed automatic transmission typically shows a gear ratiospan, which is a significant factor for securing linearity of stepratios, in a level of 6.5 to 7.5.

In addition, we have discovered that an eight-speed automatictransmission may become inferior in respect of linearity of step ratiosof shift-stages even if the gear ratio span may rise a level above 9.0.

SUMMARY

The present disclosure provides a planetary gear train realizing tenforward speeds and at least one reverse speed by utilizing fiveplanetary gear sets and six engagement elements, thereby reducing a dragloss and improving power delivery efficiency and fuel consumption.

Also, the present disclosure employs a torque-in-parallel scheme to anoutput side planetary gear set, thereby reducing torque loads ofengagement elements and improving torque delivery efficiency anddurability.

In addition, the present disclosure improves flexibility of output gearratio, thereby improving linearity of step ratios of shift-stages.

One form of planetary gear train of an automatic transmission for avehicle may include input and output shafts, first to fifth planetarygear sets respectively having first to third, fourth to sixth, seventhto ninth, tenth to twelfth, and thirteenth to fifteenth rotationalelements, a first shaft connected with the second and fifth rotationalelements and the input shaft, a second shaft connected with thefourteenth rotational element and the output shaft, a third shaftconnected with the ninth and thirteenth rotational elements, a fourthshaft connected with the tenth and fifteenth rotational elements, afifth shaft connected with the first, sixth, and seventh rotationalelements, a sixth shaft connected with the third rotational element, aseventh shaft connected with the eighth and eleventh rotational element,an eighth shaft connected with the fourth rotational element, and aninth shaft connected with the twelfth rotational element.

The planetary gear train may further include six engagement elements,each of which configured to selectively connect a corresponding pairamong the first to ninth shaft, the input shaft, the output shaft, andthe transmission housing, wherein three engagement elements areconfigured to operate for respective shift-stages.

The six engagement element may include three clutches and three brakes.

The six engagement elements may include: a first clutch arranged betweenthe second shaft and the fifth shaft, a second clutch arranged betweenthe sixth shaft and the seventh shaft, a third clutch arranged betweenthe seventh shaft and the eighth shaft, a first brake arranged betweenthe fourth shaft and the transmission housing, a second brake arrangedbetween the eighth shaft and the transmission housing, a third brakearranged between the ninth shaft and the transmission housing.

The first, second, and third rotational elements may be a first sungear, a first planet carrier, and a first ring gear of the planetarygear set. The fourth, fifth, and sixth rotational elements may be asecond sun gear, a second planet carrier, and a second ring gear of theplanetary gear set. The seventh, eighth, and ninth rotational elementsmay be a third sun gear, a third planet carrier, and a third ring gearof the planetary gear set. The tenth, eleventh, and twelfth rotationalelements may be a fourth sun gear, a fourth planet carrier, and a fourthring gear of the planetary gear set. The thirteenth, fourteenth, andfifteenth rotational elements may be a fifth sun gear, a fifth planetcarrier, and a fifth ring gear of the planetary gear set.

The first, second, third, fourth, and fifth planetary gear sets may bearranged in an order of second, first, fourth, third, and fifthplanetary gear sets from an engine side. The first, second, third,fourth, and fifth planetary gear sets may be arranged in an order ofsecond, first, third, fourth, and fifth planetary gear sets from anengine side.

Another form of the present disclosure utilizes five planetary gear setsoperated by six engagement elements, and thereby achieves the tenforward speeds and at least one reverse speed.

In addition, the gear ratio span of at least 9.8 may be achieved so asto enhance an engine driving efficiency, and a linearity of step ratiosof shift-stages may be also improved, thereby contributing to a betterdrivability of the vehicle.

While achieving ten forward speeds and at least one reverse speed,engagement element operation is minimized so as to reduce a drag loss,thereby improving power delivery efficiency and fuel efficiency.

A torque-in-parallel scheme is applied to an output side planetary gearset, and thus the torque loads may be evenly distributed to planetarygear sets and engagement elements, thereby improving torque deliveryefficiency and durability.

By using five planetary gear sets to realize ten forward speeds and atleast one reverse speed, wider range of output gear ratios may beachieved, thereby improving linearity in step ratios of shift-stages.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now bedescribed various forms thereof, given by way of example, referencebeing made to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a planetary gear train;

FIG. 2 is an operational chart of engagement elements for respectiveshift-stages applied to a planetary gear train; and

FIG. 3 is a schematic diagram of a planetary gear train.

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

In the following description, dividing names of components into first,second and the like is to divide the names because the names of thecomponents are the same as each other and an order thereof is notparticularly limited. Further, as used herein, description of elementsbeing “fixedly” connected or interconnected includes elements that arealways connected directly or indirectly, such that the fixedly connectedelements rotate at a same speed.

FIG. 1 is a schematic diagram of a planetary gear train in some forms ofthe present disclosure.

Referring to FIG. 1, a planetary gear train in some forms of the presentdisclosure includes first, second, third, fourth, and fifth planetarygear sets PG1, PG2, PG3, PG4, and PG5 arranged on a same axis, an inputshaft IS, an output shaft OS, nine shafts TM1 to TM9 interconnectingrotational elements of the first, second, third, fourth, and fifthplanetary gear sets PG1, PG2, PG3, PG4, and PG5, engagement elements ofthree clutches C1 to C3 and three brakes B1 to B3, and a transmissionhousing H.

A torque of an engine input to the input shaft IS is shifted bycooperative operation of the first, second, third, fourth, and fifthplanetary gear sets PG1, PG2, PG3, PG4, and PG5, and a shifted torque isoutput through the output shaft OS.

In some forms of the present disclosure, the planetary gear sets arearranged in the order of the second, the first, and the fourth, third,fifth planetary gear set PG2, PG1, PG4, PG3, and PG5, from an engineside.

The input shaft IS is an input member and the torque from a crankshaftof an engine is input into the input shaft IS, after beingtorque-converted through a torque converter.

The output shaft OS is an output member arranged on the same axis withthe input shaft IS, and transmits the shifted torque to a drive shaftthrough a differential apparatus.

The first planetary gear set PG1 is a single pinion planetary gear set,and includes a first sun gear S1, a first planet carrier PC1 rotatablysupporting a plurality of first pinion gears P1 externally gear-meshedwith the first sun gear S1, and a first ring gear R1 internallygear-meshed with the plurality of first pinion gears P1. The first sungear S1 acts as a first rotational element N1, the first planet carrierPC1 acts as a second rotational element N2, and the first ring gear R1acts as a third rotational element N3.

The second planetary gear set PG2 is a single pinion planetary gear set,and includes a second sun gear S2, a second planet carrier PC2 rotatablysupporting a plurality of second pinion gears P2 externally gear-meshedwith the second sun gear S2, and a second ring gear R2 internallygear-meshed with the plurality of second pinion gears P2. The second sungear S2 acts as a fourth rotational element N4, the second planetcarrier PC2 acts as a fifth rotational element N5, and the second ringgear R2 acts as a sixth rotational element N6.

The third planetary gear set PG3 is a single pinion planetary gear set,and includes a third sun gear S3, a third planet carrier PC3 rotatablysupporting a plurality of third pinion gears P3 externally gear-meshedwith the third sun gear S3, and a third ring gear R3 internallygear-meshed with the plurality of third pinion gears P3. The third sungear S3 acts as a seventh rotational element N7, the third planetcarrier PC3 acts as an eighth rotational element N8, and the third ringgear R3 acts as a ninth rotational element N9.

The fourth planetary gear set PG4 is a single pinion planetary gear set,and includes a fourth sun gear S4, a fourth planet carrier PC4 rotatablysupporting a plurality of fourth pinion gears P4 externally gear-meshedwith the fourth sun gear S4, and a fourth ring gear R4 internallygear-meshed with the plurality of fourth pinion gears P4. The fourth sungear S4 acts as a tenth rotational element N10, the fourth planetcarrier PC4 acts as a eleventh rotational element N11, and the fourthring gear R4 acts as a twelfth rotational element N12.

The fifth planetary gear set PG5 is a single pinion planetary gear set,and includes a fifth sun gear S5, a fifth planet carrier PC5 rotatablysupporting a plurality of fifth pinion gears P5 externally gear-meshedwith the fifth sun gear S5, and a fifth ring gear R5 internallygear-meshed with the plurality of fifth pinion gears P5. The fifth sungear S5 acts as a thirteenth rotational element N13, the fifth planetcarrier PC5 acts as a fourteenth rotational element N14, and the fifthring gear R5 acts as a fifteenth rotational element N15.

In the arrangement of the first, second, third, fourth, and fifthplanetary gear sets PG1, PG2, PG3, PG4, and PG5, the second rotationalelement N2 and the fifth rotational element N5 are fixedlyinterconnected, the first rotational element N1 and the sixth rotationalelement N6 and seventh rotational element N7 are fixedly interconnected,the eighth rotational element N8 and the eleventh rotational element N11are fixedly interconnected, the ninth rotational element N9 and thethirteenth rotational element N13 are fixedly interconnected, the tenthrotational element N10 and the fifteenth rotational element N15 arefixedly interconnected, and nine shafts TM1 to TM9 are formed.

The nine shafts TM1 to TM9 are hereinafter described in detail.

Each of the ten shafts TM1 to TM9 may be a rotational member thatfixedly interconnects the input and output shafts and rotationalelements of the planetary gear sets PG1, PG2, PG3, PG4, and PG5, or maybe a rotational member that selectively interconnects a rotationalelement to the transmission housing H, or may be a fixed member fixed tothe transmission housing H.

The first shaft TM1 is connected with the second rotational element N2(first planet carrier PC1) and the fifth rotational element N5 (secondplanet carrier PC2), and fixedly connected with the input shaft IS,thereby always acting as an input element.

The second shaft TM2 is connected with the fourteenth rotational element(N14: fifth planet carrier PC5), and fixedly connected with the outputshaft OS, thereby always acting as an output element.

The third shaft TM3 is connected with the ninth rotational element N9(third ring gear R3) and the thirteenth rotational element N13 (fifthsun gear S5).

The fourth shaft TM4 is connected with the tenth rotational element N10(fourth sun gear S4) and the fifteenth rotational element N15 (fifthring gear R5).

The fifth shaft TM5 is connected with the first rotational element N1(first sun gear S1), the sixth rotational element N6 (second ring gearR2), and the seventh rotational element N7 (third sun gear S3).

The sixth shaft TM6 is connected with third rotational element N3 (firstring gear R1).

The seventh shaft TM7 is connected with the eighth rotational element N8(third planet carrier PC3) and the eleventh rotational element N11(fourth planet carrier PC4).

The eighth shaft TM8 is connected with the fourth rotational element N4(second sun gear S2).

The ninth shaft TM9 is connected with twelfth rotational element N12(fourth ring gear R4).

The second shaft TM2 is selectively connected with the fifth shaft TM5,and the sixth shaft TM6 and the eighth shaft TM8 are selectivelyconnected with the seventh shaft TM7.

In addition, the fourth shaft TM4, the eighth shaft TM8, and ninth shaftTM9 are selectively connected with the transmission housing H, therebyselectively acting as a fixed element.

The three engagement elements of clutches C1, C2, and C3 are arrangedbetween the nine shafts TM1 to TM9, the input shaft IS, and the outputshaft OS, so as to form selective connections.

The three engagement elements of brakes B1, B2, and B3 are arrangedbetween the nine shafts TM1 to TM9 and the transmission housing H, so asto form selective connections.

The six engagement element of the three clutches C1 to C3 and the threebrakes B1 to B3 are arranged as follows.

The first clutch C1 is arranged between the second shaft TM2 and thefifth shaft TM5, and selectively connects the second shaft TM2 and thefifth shaft TM5, thereby controlling power delivery therebetween.

The second clutch C2 is arranged between the sixth shaft TM6 and theseventh shaft TM7, and selectively connects the sixth shaft TM6 and theseventh shaft TM7, thereby controlling power delivery therebetween.

The third clutch C3 is arranged between the seventh shaft TM7 and theeighth shaft TM8, and selectively connects the seventh shaft TM7 and theeighth shaft TM8, thereby controlling power delivery therebetween.

The first brake B1 is arranged between the fourth shaft TM4 and thetransmission housing H, and selectively connects the fourth shaft TM4 tothe transmission housing H.

The second brake B2 is arranged between the eighth shaft TM8 and thetransmission housing H, and selectively connects the eighth shaft TM8 tothe transmission housing H.

The third brake B3 is arranged between the ninth shaft TM9 and thetransmission housing H, and selectively connects the ninth shaft TM9 tothe transmission housing H.

The engagement elements of the first, second, and third clutches C1, C2,and C3 and the first, second, and third brakes B1, B2, and B3 may berealized as multi-plate hydraulic pressure friction devices that arefrictionally engaged by hydraulic pressure, however, it should not beunderstood to be limited thereto, since various other configuration thatare electrically controllable may be available.

FIG. 2 is an operational chart of engagement elements for respectiveshift-stages applied to a planetary gear train in some forms of thepresent disclosure.

Referring to FIG. 2, a planetary gear train in some forms of the presentdisclosure realizes ten forward speeds and at least one reverse speed byoperating three engagements among the first, second, and third clutchesC1, C2, and C3 and first, second, third brake B1, B2, and B3.

In the forward first speed D1, the second clutch C2 and the first andsecond brakes B1 and B2 are simultaneously operated.

As a result, the sixth shaft TM6 is connected with the seventh shaft TM7by the operation of the second clutch C2. In this state, the inputtorque is input to the first shaft TM1.

In addition, the fourth and eighth shafts TM4 and TM8 act as a fixedelement by the operation of the first and second brakes B1 and B2,thereby realizing the forward first speed and outputting a shiftedtorque to the output shaft OS connected with the second shaft TM2.

In the forward second speed D2, the second and third clutches C2 and C3and the first brake B1 are simultaneously operated.

As a result, the sixth shaft TM6 is connected with the seventh shaft TM7by the operation of the second clutch C2, and the seventh shaft TM7 isinterconnected with the eighth shaft TM8 by the operation of the thirdclutch C3. In this state, the input torque is input to the first shaftTM1.

In addition, the fourth shaft TM4 acts as a fixed element by theoperation of the first brake B1, thereby realizing the forward secondspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In the forward third speed D3, the first and second clutch C1 and C2 andthe first brake B1 are simultaneously operated.

As a result, the second shaft TM2 is connected with the fifth shaft TM5by the operation of the first clutch C1, and the sixth shaft TM6 isinterconnected with the seventh shaft TM7 by the operation of the secondclutch C2. In this state, the input torque is input to the first shaftTM1.

In addition, the fourth shaft TM4 acts as a fixed element by theoperation of the first brake B1, thereby realizing the forward thirdspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In the forward fourth speed D4, the first and third clutches C1 and C3and the first brake B1 are simultaneously operated.

As a result, the second shaft TM2 is connected with the fifth shaft TM5by the operation of the first clutch C1, and the seventh shaft TM7 isinterconnected with the eighth shaft TM8 by the operation of the thirdclutch C3. In this state, the input torque is input to the first shaftTM1.

In addition, the fourth shaft TM4 acts as a fixed element by theoperation of the first brake B1, thereby realizing the forward fourthspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In the forward fifth speed D5, the first, second, and third clutches C1,C2, and C3 are simultaneously operated.

As a result, the second shaft TM2 is connected with the fifth shaft TM5by the operation of the first clutch C1, and the sixth shaft TM6 isinterconnected with the seventh shaft TM7 by the operation of the secondclutch C2, and the seventh shaft TM7 is interconnected with the eighthshaft TM8 by the operation of the third clutch C3. In this state, theinput torque is input to the first shaft TM1.

Then, the first, second, third, fourth, and fifth planetary gear setsPG1, PG2, PG3, PG4, and PG5 integrally rotate, and the torque receivedat the first shaft TM1 is outputted as inputted, thereby realizing theforward fifth speed and outputting a shifted torque through the outputshaft OS connected with the second shaft TM2.

In the forward sixth speed D6, the first and third clutches C1 and C3and the third brake B3 are simultaneously operated.

As a result, the second shaft TM2 is connected with the fifth shaft TM5by the operation of the first clutch C1, and the seventh shaft TM7 isinterconnected with the eighth shaft TM8 by the operation of the thirdclutch C3. In this state, the input torque is input to the first shaftTM1.

In addition, the ninth shaft TM9 acts as a fixed element by theoperation of the third brake B3, thereby realizing the forward sixthspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In the forward seventh speed D7, the first clutch C1 and the second andthird brakes B2 and B3 are simultaneously operated.

As a result, the second shaft TM2 is connected with the fifth shaft TM5by the operation of the first clutch C1. In this state, the input torqueis input to the first shaft TM1.

In addition, the eighth and ninth shafts TM8 and TM9 act as a fixedelement by the operation of the second, third brake B2 and B3, therebyrealizing the forward seventh speed and outputting a shifted torque tothe output shaft OS connected with the second shaft TM2.

In the forward eighth speed D8, the first and second clutch C1 and C2and the third brake B3 are simultaneously operated.

As a result, the second shaft TM2 is connected with the fifth shaft TM5by the operation of the first clutch C1, and the sixth shaft TM6 isinterconnected with the seventh shaft TM7 by the operation of the secondclutch C2. In this state, the input torque is input to the first shaftTM1.

In addition, the ninth shaft TM9 acts as a fixed element by theoperation of the third brake B3, thereby realizing the forward eighthspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In the forward ninth speed D9, the second clutch C2 and the second andthird brakes B2 and B3 are simultaneously operated.

As a result, the sixth shaft TM6 is connected with the seventh shaft TM7by the operation of the second clutch C2. In this state, the inputtorque is input to the first shaft TM1.

In addition, the eighth and ninth shafts TM8 and TM9 act as a fixedelement by the operation of the second, third brake B2 and B3, therebyrealizing the forward ninth speed and outputting a shifted torque to theoutput shaft OS connected with the second shaft TM2.

In the forward tenth speed D10, the second and third clutches C2 and C3and the third brake B3 are simultaneously operated.

As a result, the sixth shaft TM6 is connected with the seventh shaft TM7by the operation of the second clutch C2, and the seventh shaft TM7 isinterconnected with the eighth shaft TM8 by the operation of the thirdclutch C3. In this state, the input torque is input to the first shaftTM1.

In addition, the ninth shaft TM9 acts as a fixed element by theoperation of the third brake B3, thereby realizing the forward tenthspeed and outputting a shifted torque to the output shaft OS connectedwith the second shaft TM2.

In some forms of the present disclosure, three reverse speeds areavailable.

In the reverse first speed REV1, the third clutch C3 and the first andsecond brakes B1 and B2 are simultaneously operated.

As a result, the seventh shaft TM7 is connected with the eighth shaftTM8 by the operation of the third clutch C3. In this state, the inputtorque is input to the first shaft TM1.

In addition, the fourth and eighth shafts TM4 and TM8 act as a fixedelement by the operation of the first and second brakes B1 and B2,thereby realizing the reverse speed and outputting a shifted torque tothe output shaft OS connected with the second shaft TM2.

In the reverse second speed REV2, the third clutch C3 and the first andthird brakes B1 and B3 are simultaneously operated.

As a result, the seventh shaft TM7 is connected with the eighth shaftTM8 by the operation of the third clutch C3. In this state, the inputtorque is input to the first shaft TM1.

In addition, the fourth and ninth shafts TM4 and TM9 act as a fixedelement by the operation of the first, third brake B1 and B3, therebyrealizing the reverse speed and outputting a shifted torque to theoutput shaft OS connected with the second shaft TM2.

In the reverse third speed REV3, the first, second, and third brakes B1,B2, and B3 are simultaneously operated.

As a result, an input torque is input to the first shaft TM1.

In addition, the fourth and eighth, ninth shafts TM4, TM8, and TM9 actas a fixed element by the operation of the first, second, third brakeB1, B2, and B3, thereby realizing the reverse speed and outputting ashifted torque to the output shaft OS connected with the second shaftTM2.

FIG. 3 is a schematic diagram of a planetary gear train in some forms ofthe present disclosure.

According to a planetary gear train in some forms of the presentdisclosure shown in FIG. 1, the planetary gear sets are arranged in anorder of second, first, fourth, third, and fifth planetary gear setsPG2, PG1, PG4, PG3, and PG5 from an engine side. However, according to aplanetary gear train in some forms of the present disclosure shown inFIG. 3, the planetary gear sets are arranged in an order of second,first, third, fourth, and fifth planetary gear sets PG2, PG1, PG3, PG4,and PG5 from an engine side.

Such a form only differs in terms of the arrangement of the planetarygear set, and shows the same connection relations between the nineshafts TM1 to TM9, three clutches C1, C2, and C3, and three brakes B1 toB3, thereby providing the same operation.

As described above, a planetary gear train in some forms of the presentdisclosure utilizes five planetary gear sets PG1, PG2, PG3, PG4, and PG5operated by six engagement elements of three clutches C1, C2, and C3 andthree brakes B1, B2, and B3, and thereby achieves the ten forward speedsand at least one reverse speed.

In addition, the gear ratio span of at least 9.8 may be achieved so asto enhance an engine driving efficiency, and a linearity of step ratiosof shift-stages may be improved as well, thereby contributing to abetter drivability of the vehicle.

While achieving ten forward speeds and at least one reverse speed,engagement element operation is minimized so as to reduce a drag loss,thereby improving power delivery efficiency and fuel efficiency.

A torque-in-parallel scheme is applied to an output side planetary gearset, and thus the torque loads may be evenly distributed to planetarygear sets and engagement elements, thereby improving torque deliveryefficiency and durability.

By using five planetary gear sets to realize ten forward speeds and atleast one reverse speed, wider range of output gear ratios may beachieved, thereby improving linearity in step ratios of shift-stages.

The description of the disclosure is merely exemplary in nature and,thus, variations that do not depart from the substance of the disclosureare intended to be within the scope of the disclosure. Such variationsare not to be regarded as a departure from the spirit and scope of thedisclosure.

DESCRIPTION OF SYMBOLS

-   PG1, PG2, PG3, PG4, PG5: first, second, third, fourth, and fifth    planetary gear sets-   S1, S2, S3, S4, S5: first, second, third, fourth, and fifth sun    gears-   PC1, PC2, PC3, PC4, PC5: first, second, third, fourth, and fifth    planet carriers-   R1, R2, R3, R4, R5: first, second, third, fourth, and fifth ring    gears-   C1, C2, C3: first, second, and third clutches-   B1, B2, B3: first, second, and third brakes-   IS: input shaft-   OS: output shaft-   TM1, TM2, TM3, TM4, TMS, TM6, TM7, TM8, TM9: first, second, third,    fourth, fifth, sixth, seventh, eighth, and ninth shafts

What is claimed is:
 1. A planetary gear train of an automatictransmission for a vehicle, comprising: an input shaft configured toreceive an external torque; an output shaft configured to output ashifted torque; a first planetary gear set having first, second, andthird rotational elements; a second planetary gear set having fourth,fifth, and sixth rotational elements; a third planetary gear set havingseventh, eighth, and ninth rotational elements; a fourth planetary gearset having tenth, eleventh, and twelfth rotational elements; a fifthplanetary gear set having thirteenth, fourteenth, and fifteenthrotational elements; a first shaft fixedly connected with the secondrotational element, the fifth rotational element, and the input shaft; asecond shaft fixedly connected with the fourteenth rotational elementand the output shaft; a third shaft fixedly connected with the ninthrotational element and the thirteenth rotational element; a fourth shaftfixedly connected with the tenth rotational element and the fifteenthrotational element; a fifth shaft fixedly connected with the firstrotational element, the sixth rotational element, and the seventhrotational element; a sixth shaft fixedly connected with the thirdrotational element; a seventh shaft fixedly connected with the eighthrotational element and the eleventh rotational element; an eighth shaftfixedly connected with the fourth rotational element; and a ninth shaftfixedly connected with the twelfth rotational element.
 2. The planetarygear train of claim 1, further comprising: six engagement elements,wherein each engagement element is configured to selectively connect acorresponding pair among the first to ninth shaft, the input shaft, theoutput shaft, and the transmission housing, and wherein three engagementelements are configured to operate for respective shift-stages.
 3. Theplanetary gear train of claim 2, wherein the six engagement elementscomprise three clutches and three brakes.
 4. The planetary gear train ofclaim 2, wherein the six engagement elements comprise: a first clutcharranged between the second shaft and the fifth shaft; a second clutcharranged between the sixth shaft and the seventh shaft; a third clutcharranged between the seventh shaft and the eighth shaft; a first brakearranged between the fourth shaft and the transmission housing; a secondbrake arranged between the eighth shaft and the transmission housing;and a third brake arranged between the ninth shaft and the transmissionhousing.
 5. The planetary gear train of claim 1, wherein: the first,second, and third rotational elements of the first planetary gear setare respectively a first sun gear, a first planet carrier, and a firstring gear of the first planetary gear set; the fourth, fifth, and sixthrotational elements of the second planetary gear set are respectively asecond sun gear, a second planet carrier, and a second ring gear of thesecond planetary gear set; the seventh, eighth, and ninth rotationalelements of the third planetary gear set are respectively a third sungear, a third planet carrier, and a third ring gear of the thirdplanetary gear set; the tenth, eleventh, and twelfth rotational elementsof the fourth planetary gear set are respectively a fourth sun gear, afourth planet carrier, and a fourth ring gear of the fourth planetarygear set; and the thirteenth, fourteenth, and fifteenth rotationalelements of the fifth planetary gear set are respectively a fifth sungear, a fifth planet carrier, and a fifth ring gear of the fifthplanetary gear set.
 6. The planetary gear train of claim 1, wherein thefirst, second, third, fourth, and fifth planetary gear sets are arrangedin an order of second, first, fourth, third, and fifth planetary gearsets from an engine side.
 7. The planetary gear train of claim 1,wherein the first, second, third, fourth, and fifth planetary gear setsare arranged in an order of second, first, third, fourth, and fifthplanetary gear sets from the engine side.
 8. A planetary gear train ofan automatic transmission for a vehicle, comprising: an input shaftconfigured to receive an external torque; an output shaft configured tooutput a shifted torque; a first planetary gear set having first,second, and third rotational elements; a second planetary gear sethaving fourth, fifth, and sixth rotational elements; a third planetarygear set having seventh, eighth, and ninth rotational elements; a fourthplanetary gear set having tenth, eleventh, and twelfth rotationalelements; a fifth planetary gear set having thirteenth, fourteenth, andfifteenth rotational elements; a first shaft fixedly connected with thesecond rotational element, the fifth rotational element, and the inputshaft; a second shaft fixedly connected with the fourteenth rotationalelement and the output shaft; a third shaft fixedly connected with theninth rotational element and the thirteenth rotational element; a fourthshaft fixedly connected with the tenth rotational element and thefifteenth rotational element; a fifth shaft fixedly connected with thefirst rotational element and the sixth rotational element and seventhrotational element; a sixth shaft fixedly connected with the thirdrotational element; a seventh shaft fixedly connected with the eighthrotational element and the eleventh rotational element; and a pluralityof shafts comprising a rotation element of the second and fourthplanetary gear set that is not fixedly connected with any of the firstto seventh shafts, wherein any shaft of the plurality of shafts isconfigured to selectively connect to the transmission housing.
 9. Theplanetary gear train of claim 8, wherein the plurality of shaftscomprise: an eighth shaft fixedly connected with the fourth rotationalelement; and a ninth shaft fixedly connected with the twelfth rotationalelement.
 10. The planetary gear train of claim 9, further comprising:three clutches, each of the three clutches configured to interconnectany two shafts selected from the nine shafts; and three brakes, each ofthe three brakes configured to selectively connect a corresponding shaftamong the nine shafts to the transmission housing, wherein thecorresponding shaft is not connected with the input shaft or the outputshaft.
 11. The planetary gear train of claim 10, wherein the threeclutches comprise: a first clutch arranged between the second shaft andthe fifth shaft; a second clutch arranged between the sixth shaft andthe seventh shaft; and a third clutch arranged between the seventh shaftand the eighth shaft, and wherein the three brakes comprise: a firstbrake arranged between the fourth shaft and the transmission housing; asecond brake arranged between the eighth shaft and the transmissionhousing; and a third brake arranged between the ninth shaft and thetransmission housing.
 12. The planetary gear train of claim 8, wherein:the first, second, and third rotational elements of the first planetarygear set are respectively a first sun gear, a first planet carrier, anda first ring gear of the first planetary gear set; the fourth, fifth,and sixth rotational elements of the second planetary gear set arerespectively a second sun gear, a second planet carrier, and a secondring gear of the second planetary gear set; the seventh, eighth, andninth rotational elements of the third planetary gear set arerespectively a third sun gear, a third planet carrier, and a third ringgear of the third planetary gear set; the tenth, eleventh, and twelfthrotational elements of the fourth planetary gear set are respectively afourth sun gear, a fourth planet carrier, and a fourth ring gear of thefourth planetary gear set; and the thirteenth, fourteenth, and fifteenthrotational elements of the fifth planetary gear set are respectively afifth sun gear, a fifth planet carrier, and a fifth ring gear of thefifth planetary gear set.
 13. The planetary gear train of claim 8,wherein the first, second, third, fourth, and fifth planetary gear setsare arranged in an order of second, first, fourth, third, and fifthplanetary gear sets from an engine side.
 14. The planetary gear train ofclaim 8, wherein the first, second, third, fourth, and fifth planetarygear sets are arranged in an order of second, first, third, fourth, andfifth planetary gear sets from the engine side.
 15. A planetary geartrain of an automatic transmission for a vehicle, comprising: an inputshaft configured to receive an external torque; an output shaftconfigured to output a shifted torque; a first planetary gear set havingfirst, second, and third rotational elements; a second planetary gearset having fourth, fifth, and sixth rotational elements; a thirdplanetary gear set having seventh, eighth, and ninth rotationalelements; a fourth planetary gear set having tenth, eleventh, andtwelfth rotational elements; a fifth planetary gear set havingthirteenth, fourteenth, and fifteenth rotational elements; a first shaftfixedly connected with the second rotational element, the fifthrotational element, and the input shaft; a second shaft fixedlyconnected with the fourteenth rotational element and the output shaft; athird shaft fixedly connected with the ninth rotational element and thethirteenth rotational element; a fourth shaft fixedly connected with thetenth rotational element and the fifteenth rotational element; a fifthshaft fixedly connected with the first rotational element and the sixthrotational element and seventh rotational element; a sixth shaft fixedlyconnected with the third rotational element; a seventh shaft fixedlyconnected with the eighth rotational element and the eleventh rotationalelement; and eighth and ninth shafts comprising a rotation element ofthe second and fourth planetary gear sets that is not fixedly connectedwith any of the first to seventh shafts, wherein the eighth and ninthshafts are configured to selectively connect to the transmission housingthrough brakes.
 16. The planetary gear train of claim 15, wherein: thesecond and fifth shafts, the sixth and seventh shafts, and the seventhand eighth shafts are configured to selectively interconnect one anotherthrough clutches; the eighth shaft is fixedly connected with the fourthrotational element; and the ninth shaft is fixedly connected with thetwelfth rotational element.
 17. The planetary gear train of claim 16,further comprising: a first clutch arranged between the second shaft andthe fifth shaft; a second clutch arranged between the sixth shaft andthe seventh shaft; a third clutch arranged between the seventh shaft andthe eighth shaft; a first brake arranged between the fourth shaft andthe transmission housing; a second brake arranged between the eighthshaft and the transmission housing; and a third brake arranged betweenthe ninth shaft and the transmission housing.
 18. The planetary geartrain of claim 15, wherein: the first, second, and third rotationalelements of the first planetary gear set are respectively a first sungear, a first planet carrier, and a first ring gear of the firstplanetary gear set; the fourth, fifth, and sixth rotational elements ofthe second planetary gear set are respectively a second sun gear, asecond planet carrier, and a second ring gear of the second planetarygear set; the seventh, eighth, and ninth rotational elements of thethird planetary gear set are respectively a third sun gear, a thirdplanet carrier, and a third ring gear of the third planetary gear set;the tenth, eleventh, and twelfth rotational elements of the fourthplanetary gear set are respectively a fourth sun gear, a fourth planetcarrier, and a fourth ring gear of the fourth planetary gear set; andthe thirteenth, fourteenth, and fifteenth rotational elements of thefifth planetary gear set are respectively a fifth sun gear, a fifthplanet carrier, and a fifth ring gear of the fifth planetary gear set.19. The planetary gear train of claim 15, wherein the first, second,third, fourth, and fifth planetary gear sets are arranged in an order ofsecond, first, fourth, third, and fifth planetary gear sets from anengine side.
 20. The planetary gear train of claim 15, wherein thefirst, second, third, fourth, and fifth planetary gear sets are arrangedin an order of second, first, third, fourth, and fifth planetary gearsets from the engine side.